Disparities in Child Welfare Referrals for Patients Seen in a Pediatric Emergency Department for Unintentional Ingestions

OBJECTIVE

To examine the characteristics of patients visiting the pediatric emergency department (PED) for unintentional ingestions and associations between patient race and ethnicity in referrals to Child Protective Services (CPS) for supervisory neglect.

METHODS

We conducted a cross-sectional analysis of children <12 years old who presented to the PED between October 2015 and December 2020 for an unintentional ingestion. Patients were identified by searching the electronic health record for diagnosis codes corresponding to unintentional ingestions. Patient demographics, ingestion type, disposition, and referrals to CPS were abstracted by manual chart review. Logistic regression models were used to evaluate associations between patient demographics and visit characteristics with referral to CPS.

RESULTS

We identified 129 PED encounters for unintentional ingestions that were included for analysis. Overall, 22 patients (17.1%) were referred to CPS for neglect. In the univariate analysis, both ingestion of an illicit drug and arrival to the PED by ambulance were associated with a higher odds of referral to CPS. In the multivariable model adjusted for parent language, ingestion type, and mode of arrival to the PED, Hispanic patients had higher odds of referral to CPS than White patients (adjusted odds ratio (aOR) = 17.2, 95% confidence intervals [1.8-162.3], P = .03). There was not a statistically significant association between Black race and referral to CPS.

CONCLUSIONS

Referrals to CPS from the PED after unintentional ingestions are common and disproportionally involve Hispanic patients. More research is needed to promote equitable child maltreatment reporting for children presenting to the PED following unintentional ingestions.

The First Statewide Implementation of a Regional Disaster Teleconsultation System to Expand Critical Care Surge Capacity: A Case Study in Vermont

Background: In December 2021, the Region 1 Disaster Health Response System, the state of Vermont, and the National Emergency Tele-Critical Care Network partnered to provide statewide access to disaster teleconsultations during COVID-19 surge conditions. In this case report, we describe how a disaster teleconsultation system was implemented in Vermont to provide access to temporary tele-critical care consultations during the Omicron COVID-19 surge. Methods: We measured the time from request of service to implementation and calculated descriptive statistics. Results: Seven of Vermont's 14 hospitals requested the service. Despite a technology solution capable of providing services within hours, mean time to service implementation was 27 days (interquartile range 20-41 days). Conclusions: Integration of disaster teleconsultation systems into state and local emergency management plans are needed to bring administrative start-up times in line with technical readiness.

Adaptation of a Simulation Model and Checklist to Assess Pediatric Emergency Care Performance by Prehospital Teams

INTRODUCTION

Simulation tools to assess prehospital team performance and identify patient safety events are lacking. We adapted a simulation model and checklist tool of individual paramedic performance to assess prehospital team performance and tested interrater reliability.

METHODS

We used a modified Delphi process to adapt 3 simulation cases (cardiopulmonary arrest, seizure, asthma) and checklist to add remote physician direction, target infants, and evaluate teams of 2 paramedics and 1 physician. Team performance was assessed with a checklist of steps scored as complete/incomplete by raters using direct observation or video review. The composite performance score was the percentage of completed steps. Interrater percent agreement was compared with the original tool. The tool was modified, and raters trained in iterative rounds until composite performance scoring agreement was 0.80 or greater (scale <0.20 = poor; 0.21-0.39 = fair, 0.40-0.59 = moderate; 0.60-0.79 = good; 0.80-1.00 = very good).

RESULTS

We achieved very good interrater agreement for scoring composite performance in 2 rounds using 6 prehospital teams and 4 raters. The original 175 step tool was modified to 171 steps. Interrater percent agreement for the final modified tool approximated the original tool for the composite checklist (0.80 vs. 0.85), cardiopulmonary arrest (0.82 vs. 0.86), and asthma cases (0.80 vs. 0.77) but was lower for the seizure case (0.76 vs. 0.91). Most checklist items (137/171, 80%) had good-very good agreement. Among 34 items with fair-moderate agreement, 15 (44%) related to patient assessment, 9 (26%) equipment use, 6 (18%) medication delivery, and 4 (12%) cardiopulmonary resuscitation quality.

CONCLUSIONS

The modified checklist has very good agreement for assessing composite prehospital team performance and can be used to test effects of patient safety interventions.

Pediatric Telehealth Use in U.S. Emergency Departments in 2019

Objectives: Little is known about the recent usage of pediatric telehealth across all emergency departments (EDs) in the United States. Building upon our prior work, we aimed to characterize the usage of ED pediatric telehealth in the pre-COVID-19 era. Methods: The 2019 National ED Inventory-USA survey characterized all U.S. EDs open in 2019. Among EDs reporting receipt of pediatric telehealth services, we selected a random sample (n = 130) for a second survey on pediatric telehealth usage (2019 ED Pediatric Telehealth Survey). We also recontacted a random sample of EDs that responded to a prior, similar 2017 ED Pediatric Telehealth Survey (n = 107), for a total of 237 EDs in the 2019 ED Pediatric Telehealth Survey sample. Results: Overall, 193 (81%) of the 237 EDs responded to the 2019 Pediatric Telehealth Survey. There were 149 responding EDs that confirmed pediatric telehealth receipt in 2019. Among these, few reported ever having a pediatric emergency medicine (PEM) physician (10%) or pediatrician (9%) available for emergency care. Although 96% of EDs reported availability of pediatric telehealth services 24 h per day, 7 days per week, the majority (60%) reported using services less than once per month and 20% reported using services every 3-4 weeks. EDs most frequently used pediatric telehealth to assist with placement and transfer coordination (91%). Conclusions: Most EDs receiving pediatric telehealth in 2019 had no PEM physician or pediatrician available. Most EDs used pediatric telehealth services infrequently. Understanding barriers to assimilation of telehealth once adopted may be important to enable improved access to pediatric emergency care expertise.

Feasibility and Acceptability of a Model Disaster Teleconsultation System for Regional Disaster Health Response

Introduction: The federally funded Region 1 Regional Disaster Health Response System (RDHRS) and the American Burn Association partnered to develop a model regional disaster teleconsultation system within a Medical Emergency Operations Center (MEOC) to support triage and specialty consultation during a no-notice mass casualty incident. Our objective was to test the acceptability and feasibility of a prototype model system in simulated disasters as proof of concept. Methods: We conducted a mixed-methods simulation study using the Technology Acceptance Model framework. Participating physicians completed the Telehealth Usability Questionnaire (TUQ) and semistructured interviews after simulations. Results: TUQ item scores rating the model system were highest for usefulness and satisfaction, and lowest for interaction quality and reliability. Conclusions: We found high model acceptance, but desire for a simpler, more reliable technology interface with better audiovisual quality for low-frequency, high-stakes use. Future work will emphasize technology interface quality and reliability, automate coordinator roles, and field test the model system.

Attitudes and training related to substance use in pediatric emergency departments

Background

In recent years, pediatric emergency departments (PED) have seen an increase in presentations related to substance use among their adolescent patient population. We aimed to examine pediatric emergency medicine (PEM) physicians’ knowledge, attitudes, and beliefs on caring for adolescents with substance use.

Methods

We conducted a cross-sectional online survey of PEM physicians through the American Academy of Pediatrics Pediatric Emergency Medicine Collaborative Research Committee (PEM-CRC) listserv. The 41-item survey contained the following domains: demographics, current protocols and education for managing adolescent substance use, and attitudes about treatment of substance use. We calculated descriptive statistics for each variable within the domains.

Results

Of 177 respondents (38.2% response rate), 55.4% were female, 45.2% aged ≥ 50 years, 78% worked in a children’s hospital, and 50.8% had > 15 years clinical practice. Overall, 77.8% reported caring for adolescents with a chief complaint related to non-opioid substance use and 26.0% opioid use at least once a month. Most (80.9%) reported feeling comfortable treating major medical complications of substance use, while less than half were comfortable treating withdrawal symptoms. 73% said that they were not interested in prescribing buprenorphine.

Conclusions

Among this national sample of PEM physicians, 3 of 4 physicians managed substance-related visits monthly, but 52% lacked comfort in managing withdrawal symptoms and 73.1% were not interested in prescribing buprenorphine. Almost all PEM physician identified substance use-related education is important but lacked access to faculty expertise or educational content. Expanded access to education and training for PEM physicians related to substance use is needed.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13722-022-00339-w.

Characterizing preferred terms for geographically distant simulations: distance, remote and telesimulation

Simulationists lack standard terms to describe new practices accommodating pandemic restrictions. A standard language around these new simulation practices allows ease of communication among simulationists in various settings.

We explored consensus terminology for simulation accommodating geographic separation of participants, facilitators or equipment. We used an iterative process with participants of two simulation conferences, with small groups and survey ranking.

Small groups (n = 121) and survey ranking (n = 54) were used with

This research has deepened our understanding of how simulationists interpret this terminology, including the derived themes: (1) physical distance/separation, (2) overarching nature of the term and (3) implications from existing terms. We further deepen the conceptual discussion on healthcare simulation aligned with the search of the terminologies. We propose there are nuances that prevent an early consensus recommendation. A taxonomy of descriptors specifying the conduct of

Characterizing preferred terms for geographically distant simulations: distance, remote and telesimulation

Simulationists lack standard terms to describe new practices accommodating pandemic restrictions. A standard language around these new simulation practices allows ease of communication among simulationists in various settings.

We explored consensus terminology for simulation accommodating geographic separation of participants, facilitators or equipment. We used an iterative process with participants of two simulation conferences, with small groups and survey ranking.

Small groups (n = 121) and survey ranking (n = 54) were used with

This research has deepened our understanding of how simulationists interpret this terminology, including the derived themes: (1) physical distance/separation, (2) overarching nature of the term and (3) implications from existing terms. We further deepen the conceptual discussion on healthcare simulation aligned with the search of the terminologies. We propose there are nuances that prevent an early consensus recommendation. A taxonomy of descriptors specifying the conduct of

Emergency Departments' Uptake of Telehealth for Stroke Versus Pediatric Care: Observational Study

BACKGROUND

Telehealth for emergency stroke care delivery (telestroke) has had widespread adoption, enabling many hospitals to obtain stroke center certification. Telehealth for pediatric emergency care has been less widely adopted.

OBJECTIVE

Our primary objective was to determine whether differences in policy or certification requirements contributed to differential uptake of telestroke versus pediatric telehealth. We hypothesized that differences in financial incentives, based on differences in patient volume, prehospital routing policy, and certification requirements, contributed to differential emergency department (ED) adoption of telestroke versus pediatric telehealth.

METHODS

We used the 2016 National Emergency Department Inventory-USA to identify EDs that were using telestroke and pediatric telehealth services. We surveyed all EDs using pediatric telehealth services (n=339) and a convenience sample of the 1758 EDs with telestroke services (n=366). The surveys characterized ED staffing, transfer patterns, reasons for adoption, and frequency of use. We used bivariate comparisons to examine differences in reasons for adoption and use between EDs with only telestroke services, only pediatric telehealth services, or both.

RESULTS

Of the 442 EDs surveyed, 378 (85.5%) indicated use of telestroke, pediatric telehealth, or both. EDs with both services were smaller in bed size, volume, and ED attending coverage than those with only telestroke services or only pediatric telehealth services. EDs with telestroke services reported more frequent use, overall, than EDs with pediatric telehealth services: 14.1% (45/320) of EDs with telestroke services reported weekly use versus 2.9% (8/272) of EDs with pediatric telehealth services (P<.001). In addition, 37 out of 272 (13.6%) EDs with pediatric telehealth services reported no consults in the past year. Across applications, the most frequently selected reason for adoption was "improving level of clinical care." Policy-related reasons (ie, for compliance with outside certification or standards or for improving ED performance on quality metrics) were rarely indicated as the most important, but these reasons were indicated slightly more often for telestroke adoption (12/320, 3.8%) than for pediatric telehealth adoption (1/272, 0.4%; P=.003).

CONCLUSIONS

In 2016, more US EDs had telestroke services than pediatric telehealth services; among EDs with the technology, consults were more frequently made for stroke than for pediatric patients. The most frequently indicated reason for adoption among all EDs was related to clinical care.

Pilot Paramedic Survey of Benefits, Risks, and Strategies for Pediatric Prehospital Telemedicine

OBJECTIVE

A national survey found prehospital telemedicine had potential clinical applications but lacked provider opinion on its use for pediatric emergency care. We aimed to (1) estimate prehospital telemedicine use, (2) describe perceived benefits and risks of pediatric applications, and (3) identify preferred utilization strategies by paramedics.

METHODS

We administered a 14-question survey to a convenience sample of 25 Massachusetts paramedics attending a regional course in 2018. Volunteer participants were offered a gift card. We compared respondents to a state database for sample representativeness. We present descriptive statistics and summarize qualitative responses.

RESULTS

Twenty-five paramedics completed the survey (100% response); 23 (96%) were male, 21 (84%) 40 years or older, and 23 (92%) in urban practice. Respondents were older and more experienced than the average Massachusetts paramedic. Few had used prehospital telemedicine for patients younger than 12 years (8%; 95% confidence interval, 10-26%). Potential benefits included paramedic training (80%), real-time critical care support (68%), risk mitigation (68%), patient documentation (72%), decision support for hospital team activation (68%), and scene visualization (76%). Time delays from telemedicine equipment use (76%) and physician consultation (64%), broadband reliability (52%), and cost (56%) were potential risks. Respondents preferred video strategies for scene visualization, physician-assisted assessment and care. More respondents felt pediatric telemedicine applications would benefit rural/suburban settings than urban ones.

CONCLUSIONS

Paramedics reported prehospital telemedicine is underutilized for children but identified potential benefits including provider telesupport, training, situational awareness, and documentation. Concerns included transportation delays, cost, and broadband availability. Video was preferred for limited pediatric exposure settings. These results inform which telemedicine applications and strategies paramedics favor for children.

Tricuspid Regurgitant Jet Velocity Point-of-Care Ultrasound Curriculum Development and Validation

INTRODUCTION

The American College of Emergency Physicians (ACEP) recommends that Emergency Medicine physicians with advanced training can evaluate right ventricular (RV) pressures via point-of-care ultrasound (POCUS) by measuring a tricuspid regurgitant jet (TRJ). We were unable to find a published curriculum to deliver education for this at any skill level. Therefore, we developed, delivered, and evaluated a curriculum for the assessment of TRJ for novice physician sonographers.

METHODS

We designed an educational intervention for novice physician sonographers. The curriculum was created using a modified Delphi methodology. All novice sonographers participated in the educational intervention which consisted of a didactic lecture followed by hands-on-deliberate practice on healthy medical student volunteers with expert feedback in a simulated setting. Sonographer's knowledge was assessed at 3 time points: pre-intervention, immediately post-intervention, and 3 months post-intervention (retention assessment) by multiple choice exam.

RESULTS

Nine novice physician sonographers participated in the intervention. Mean exam performance increased from 55.6% [standard deviation (SD) 11.3%] on the pre-intervention exam to 94.4% (SD 7.3%) on the post-intervention exam and 92.9% (SD 12.5%) on the retention exam. The mean improvement between the pre- and post- exam was +38.9% (95% CI 31.8 - 46.0), and between the pre-exam and retention exam +37.1% (95% CI 22.3 - 52.0).

CONCLUSION

Sonographer knowledge of TRJ assessment improved following a brief educational intervention as measured by exam performance. Given the expanding role of POCUS it is increasingly important to provide effective resources for teaching these skills. This work establishes the basis for further study and implementation of our TRJ curriculum.

Novice Physician Ultrasound Evaluation of Pediatric Tricuspid Regurgitant Jet Velocity

Introduction

Pulmonary hypertension, associated with high mortality in pediatric patients, is traditionally screened for by trained professionals by measuring a tricuspid regurgitant jet velocity (TRJV). Our objective was to test the feasibility of novice physician sonographers (NPS) to perform echocardiograms of adequate quality to exclude pathology (defined as TRJV > 2.5 meters per second).

Methods

We conducted a cross-sectional study of NPS to assess TRJV by echocardiogram in an urban pediatric emergency department. NPS completed an educational course consisting of a didactic curriculum and hands-on workshop. NPS enrolled a convenience sample of patients aged 7–21 years. Our primary outcome was the proportion of echocardiograms with images of adequate quality to exclude pathology. Our secondary outcome was NPS performance on four image elements. We present descriptive statistics, binomial proportions, kappa coefficients, and logistic regression analysis.

Results

Eight NPS completed 80 echocardiograms. We found 82.5% (95% confidence interval [CI], 74.2–90.8) of echocardiograms had images of adequate quality to exclude pathology. Among image elements, NPS obtained a satisfactory, apical 4-chamber view in 85% (95% CI, 77.1–92.9); positioned the color box accurately 65% (95% CI, 54.5–75.5); optimized TRJV color signal 78.7% (95% CI, 69.8–87.7); and optimized continuous-wave Doppler in 55% (95% CI, 44.1–66.0) of echocardiograms.

Conclusion

NPS obtained images of adequate quality to exclude pathology in a majority of studies; however, optimized acquisition of specific image elements varied. This work establishes the basis for future study of NPS assessment of TRJV pathology when elevated pulmonary pressures are of clinical concern.

Diagnostic Accuracy of Non-Invasive Thermal Evaluation of Ventriculoperitoneal Shunt Flow in Shunt Malfunction: A Prospective, Multi-Site, Operator-Blinded Study

BACKGROUND

Thermal flow evaluation (TFE) is a non-invasive method to assess ventriculoperitoneal shunt function. Flow detected by TFE is a negative predictor of the need for revision surgery. Further optimization of testing protocols, evaluation in multiple centers, and integration with clinical and imaging impressions prompted the current study.

OBJECTIVE

To compare the diagnostic accuracy of 2 TFE protocols, with micropumper (TFE+MP) or without (TFE-only), to neuro-imaging in patients emergently presenting with symptoms concerning for shunt malfunction.

METHODS

We performed a prospective multicenter operator-blinded trial of a consecutive series of patients who underwent evaluation for shunt malfunction. TFE was performed, and preimaging clinician impressions and imaging results were recorded. The primary outcome was shunt obstruction requiring neurosurgical revision within 7 d. Non-inferiority of the sensitivity of TFE vs neuro-imaging for detecting shunt obstruction was tested using a prospectively determined a priori margin of −2.5%.

RESULTS

We enrolled 406 patients at 10 centers. Of these, 68/348 (20%) evaluated with TFE+MP and 30/215 (14%) with TFE-only had shunt obstruction. The sensitivity for detecting obstruction was 100% (95% CI: 88%-100%) for TFE-only, 90% (95% CI: 80%-96%) for TFE+MP, 76% (95% CI: 65%-86%) for imaging in TFE+MP cohort, and 77% (95% CI: 58%-90%) for imaging in the TFE-only cohort. Difference in sensitivities between TFE methods and imaging did not exceed the non-inferiority margin.

CONCLUSION

TFE is non-inferior to imaging in ruling out shunt malfunction and may help avoid imaging and other steps. For this purpose, TFE only is favored over TFE+MP.

Characterizing Avoidable Transfer Admissions in Infants Hospitalized for Bronchiolitis

OBJECTIVES

The appropriateness of interfacility transfer admissions for bronchiolitis to pediatric centers is uncertain. We characterized avoidable transfer admissions for bronchiolitis. We hypothesized that a higher proportion of hospitalized infants transferred from a community emergency department (ED) or hospital (transfer admission) would be discharged within 48 hours with little or no intervention, compared with direct admissions from an enrolling ED (nontransfer admission).

METHODS

We analyzed a 17-center, prospective infant cohort (age <1 year) hospitalized for bronchiolitis (2011-2014). An avoidable transfer admission (primary outcome) was hospitalization for <48 hours without an intervention for severe illness in which a pediatric specialist could be beneficial (oxygen, advanced airway management, life support). Parenteral fluids and routine medications were excluded. We compared admissions by patient, ED, inpatient, and transferring hospital characteristics to identify factors associated with avoidable transfer admissions. Multivariable logistic regression was used to identify predictors of avoidable transfer admission.

RESULTS

Among 1007 infants, 558 (55%) were nontransfer admissions, 164 (16%) were transfer admissions, and 204 (20%) were referrals from clinics; 81 (8%) were missing referral type. Significantly fewer transferred infants were hospitalized for <48 hours with little or no intervention (40 of 164; 24% [95% confidence interval 18%-32%]) than nontransferred infants (199 of 558; 36% [95% confidence interval 32%-40%]; P = .007). Avoidable transfer admissions were more likely to be children of color, have nonprivate insurance, receive fewer ED interventions, and originate from small EDs. A multivariable model revealed that minority race and/or ethnicity, normal oxygenation, and small ED transfers increased odds of avoidable transfer admission.

CONCLUSIONS

Although most transferred infants hospitalized for bronchiolitis required interventions for severe illness, 1 in 4 admissions were potentially avoidable.

Comparison of rapid cranial MRI to CT for ventricular shunt malfunction

OBJECTIVES

To compare the accuracy of rapid cranial magnetic resonance imaging (MRI) with that of computed tomography (CT) for diagnosing ventricular shunt malfunction.

METHODS

We performed a single-center, retrospective cohort study of children ≤21 years of age who underwent either rapid cranial MRI or cranial CT in the emergency department (ED) for evaluation of possible ventricular shunt malfunction. Each neuroimaging study was classified as "normal" (unchanged or decreased ventricle size) or "abnormal" (increased ventricle size). We classified a patient as having a ventricular shunt malfunction if operative revision for relief of mechanical causes of altered shunt flow was needed within 72 hours of initial ED evaluation. Our primary analysis tested noninferiority of the accuracy of rapid cranial MRI to CT for diagnosing shunt malfunction (noninferiority margin 10%).

RESULTS

We included 698 ED visits for 286 unique patients, with a median age at visit of 10.0 years (interquartile range 5.9-15.5 years). Patients underwent CT in 336 (48%) or rapid cranial MRI in 362 (52%) of ED visits for evaluation of possible shunt malfunction. Patients had operative revision for ventricular shunt malfunction in 140 ED visits (20%). The accuracy of rapid cranial MRI was not inferior to that of CT scan for diagnosing ventricular shunt malfunction (81.8% MRI vs 82.4% CT; risk difference 2.0%; 95% confidence interval, -4.2% to 8.2%).

CONCLUSIONS

Rapid cranial MRI was not inferior to CT for diagnosing ventricular shunt malfunction and offers the advantage of sparing a child ionizing radiation exposure.

Enols as potent antibacterial agents

This paper describes the discovery of alpha-trifluoroketoacetamides as potent antibacterial agents against Gram-positive organisms. The initial SAR indicates that the aryl ethyl side chain is essential in maintaining antibacterial activity. The SAR observations have been utilized to design a bioisostere for the alpha-trifluoroketoacetamide with good activity against Gram-positive organisms.

Human apolipoprotein E4 accelerates beta-amyloid deposition in APPsw transgenic mouse brain

The human apolipoprotein E4 (ApoE4) isoform is associated with genetic risk for Alzheimer's disease. To assess the effects of different ApoE isoforms on amyloid plaque formation, human ApoE3 and ApoE4 were expressed in the brains of transgenic mice under the control of the human transferrin promoter. Mice were crossed with transgenic mice expressing human amyloid precursor protein containing the Swedish mutation (APPsw), which facilitates amyloid beta peptide (A beta) production. The following progeny were selected for characterization: APPsw+/- x ApoE3+/- and APPsw+/-, APPsw+/- x ApoE4+/- and APPsw+/- littermates. All mice analyzed were wild type for the endogenous mouse APP and ApoE genes. Mice expressing ApoE4 in combination with APPsw have accelerated A beta deposition in the brain as assessed by enzyme immunoassay for A beta40 and A beta42 extractable in 70% formic acid, by assessment of amyloid plaque formation using thioflavin-S staining, and by immunohistochemical staining with antibodies specific for A beta40 or A beta42 and the 4G8 monoclonal or 162 polyclonal antibody. No difference in the rate of A beta deposition in the brain was seen in mice expressing ApoE3 in combination with APPsw. Thus, our data are consistent with the observation in Alzheimer's disease that ApoE4 is associated with increased accumulation of A beta in the brain relative to ApoE3.

3-Arylpiperidines as potentiators of existing antibacterial agents

Important resistance patterns in Gram-negative pathogens include active efflux of antibiotics out of the cell via a cellular pump and decreased membrane permeability. A 3-arylpiperidine derivative (1) has been identified by high-throughput assay as a potentiator with an IC(50) approximately 90 microM. This report details the evaluation of the tether length, aryl substitution and the importance of the fluorine on antibiotic accumulation. Evaluation of various tether lengths demonstrated that the two-carbon tethered analogues are optimal. Removal of the fluorine has a modest effect on antibiotic accumulation and the defluorinated analogue 17 is equally potent to the original lead 1.

An approach for assessment of water quality using semipermeable membrane devices (SPMDs) and bioindicator tests

As an integral part of our continued development of water quality assessment approaches, we combined integrative sampling, instrumental analysis of widely occurring anthropogenic contaminants, and the application of a suite of bioindicator tests as a specific part of a broader survey of ecological conditions, species diversity, and habitat quality in the Santa Cruz River in Arizona, USA. Lipid-containing semipermeable membrane devices (SPMDs) were employed to sequester waterborne hydrophobic chemicals. Instrumental analysis and a suite of bioindicator tests were used to determine the presence and potential toxicological relevance of mixtures of bioavailable chemicals in two major water sources of the Santa Cruz River. The SPMDs were deployed at two sites; the effluent weir of the International Wastewater Treatment Plant (IWWTP) and the Nogales Wash. Both of these systems empty into the Santa Cruz River and the IWWTP effluent is a potential source of water for a constructed wetland complex. Analysis of the SPMD sample extracts revealed the presence of organochlorine pesticides (OCs), polychlorinated biphenyls (PCBs), and polycyclic aromatic hydrocarbons (PAHs). The bioindicator tests demonstrated increased liver enzyme activity, perturbation of neurotransmitter systems and potential endocrine disrupting effects (vitellogenin induction) in fish exposed to the extracts. With increasing global demands on limited water resources, the approach described herein provides an assessment paradigm applicable to determining the quality of water in a broad range of aquatic systems.

Tetrazole and carboxylate groups of angiotensin receptor antagonists bind to the same subsite by different mechanisms

To identify specific interactions between either the tetrazole or carboxylate pharmacophores of non-peptide antagonists and the rat AT1 receptor, 6 basic residues were examined by site-directed mutagenesis. Three of the mutants (H183Q, H256Q, and H272Q) appeared to be like wild type. Lys102 and Arg167 mutants displayed reduced binding of the non-peptide antagonist losartan. Examination of their properties employing group-specific angiotensin II analogues indicated that their effects on binding were indirect. Interestingly, the affinity of losartan was not altered by a K199Q mutation, but the same mutation reduced the affinity of angiotensin II, the antagonist [Sar1,Ile8]angiotensin II, and several carboxylate analogues of losartan. An Ala199 substitution reduced the affinity of peptide analogues to a larger extent as compared to the affinity of losartan. Thus, the crucial acidic pharmacophores of angiotensin and losartan appear to occupy the same space within the receptor pocket, but the protonated amino group of Lys199 is not essential for binding the tetrazole anion. The binding of the tetrazole moiety with the AT1 receptor involves multiple contacts with residues such as Lys199 and His256 that constitute the same subsite of the ligand binding pocket. However, this interaction does not involve a conventional salt bridge, but rather an unusual lysine-aromatic interaction.

Severe atherosclerosis in transgenic mice expressing simian cholesteryl ester transfer protein

Cholesteryl ester transfer protein (CETP) is a plasma protein that mediates the exchange of neutral lipids among the lipoprotein. Because the principal core lipid of very-low-density lipoprotein (VLDL) is triglyceride and that of high-density lipoprotein (HDL) is cholesterol ester, CETP mediates a 'heteroexchange' of cholesterol ester for triglyceride between those lipoproteins. As a result, animals that express CETP tend to have higher VLDL and low-density lipoprotein (LDL) cholesterol levels, whereas those with no CETP activity tend to have high HDL cholesterol levels. Because VLDL and LDL are associated with the progression of atherosclerosis, and HDL are considered anti-atherogenic, CETP could be an 'atherogenic' protein, that is, given the other conditions required for atherosclerosis to develop, expression of CETP would accelerate the rate at which the arterial lesions progress. We report here that transgenic mice expressing CETP had much worse atherosclerosis than did non-expressing controls, and we suggest that the increase in lesion severity was due largely to CETP-induced alterations in the lipoprotein profile.

Structure of the murine gene encoding apolipoprotein A-I

A 1.6-kb DNA fragment containing the gene encoding apolipoprotein A-I from the mouse, Mus musculus, has been cloned and sequenced. It contains three exons separated by two introns and encodes a secreted polypeptide of 262 amino acids (aa), 238 of which constitute the mature protein. Comparisons with the rat and human proteins indicate moderate levels of shared identity (71 and 66%, respectively), although the overall aa compositions yield proteins with identical pIs (5.4). Kyte-Doolittle analyses of the three proteins indicate that there is no significant difference in the structure of these apolipoproteins.

Development of venous occlusions in mice transgenic for the plasminogen activator inhibitor-1 gene

The fibrinolytic potential of the vasculature is modulated primarily by the availability and activity of plasminogen activators, which convert the zymogen plasminogen into the active fibrin-degrading enzyme plasmin. The activities of these key regulatory enzymes are directly neutralized by their primary endogenous inhibitor, plasminogen activator inhibitor-1 (PAI-1). Although some individuals with a tendency to develop thrombotic disorders exhibit elevated levels of PAI-1 in their plasma, the cause-and-effect relationship between increased PAI-1 and thrombosis is still unclear. Specifically, it is not known whether chronic depression of fibrinolytic activity results in the development of thrombosis. To address this question we developed transgenic mice in which the contribution of PAI-1 to thrombus formation could be evaluated. The results presented in this report indicate that elevated levels of PAI-1 contribute to the development of venous but not arterial occlusions.